This invention is concerned with constructional elements known generally as structural cores. Specifically the invention relates to a core medium which replaces quasi-isotropic surfaces, or constructional cores of the honey comb type.
Structural cores are the subject of several U.S. Pat. Nos. such as 3,689,345, 3,813,273 and 3,642,566. These cores are in the form of open-ended polyhedrons joined together along common edges or sides. Such structural core media are generating high industrial interest because of the great strengths they possess relative to their weights. Aircraft constructional cores, for example, must possess quasi-isotropic load-carring capabilities, including tension, compression, bending and torsional rigidity. Structural core media thus have many uses in the aircraft and other fields.
The structural core medium with which this invention is concerned is similar to that described in U.S. Pat. Nos. 3,645,833 and 3,657,059. A core of interwoven fibrous filaments is described, coated with plastic to make the core medium. The ultimate core medium is highly satisfactory. However, it is subject to the disadvantage that the fiberous filaments must be wound on a jig to form the interwoven filament core.